The field of the disclosure relates generally to flight control systems and, more specifically, to a flight control system for controlling a horizontal stabilizer of an aircraft.
At least some known flight control systems include actuator control electronics (ACE) that collect sensor input and data from various other avionics to determine how to command a given flight control surface. The ACE generally includes a processing device that responds directly to pilot input, to sensor input, or to data received from another flight control computer to generate a control signal to control the flight control surface. The control signal generally commands a direction and rate of rotation or actuation, and is received by a remote electronics unit (REU) that actually controls an actuator, e.g., a hydraulic actuator or an electric actuator. The REU carries out the commanded rotation or actuation for a period of time or until a new command is received. In alternative embodiments, the control signal commands a position and the REU maintains the flight control surface in that position using a closed-loop position control system.
Some known flight control systems utilize redundant ACE to independently determine and agree on how to command a particular flight control surface. For example, a horizontal stabilizer, which provides pitch control of the aircraft, has a high level of authority over the aircraft and, therefore, commands for control of the horizontal stabilizer are often subject to redundancy requirements to ensure proper control of the flight control surface during normal operation as well as in failure conditions. Failure conditions include, for example, a failure of an ACE or REU. During such a failure, the flight control system must maintain control of the flight control surface, e.g., the horizontal stabilizer. Accordingly, many known flight control systems include redundant flight control paths that can maintain control through failure of an ACE, an REU, a stabilizer control module (STCM), or any other component of the flight control system. Such flight control systems typically include redundant ACE, REU, and STCM.
In contrast, for example, at least some aircraft include multiple elevators, i.e., a left elevator and a right elevator. One elevator might have multiple actuators, each actuator having an ACE and an REU. Given that the authority of the elevators is divided among numerous flight control surfaces and potentially multiple actuators, the REU is generally not required to rely on multiple ACE for command.